Lock



April 22, 1930. A. c; STQEVENS' LOCK Filed March 25, 1925 VEU5' A1"thUr115m 5 P 6 M,. n h E #1 Q A Q 1 3. f z v J safe-guards Patented Apr. 22,1930 UNITED STATES PATENT OFFICE ARTHUR C. STEVENS,

'LIP W. GROSS AND ONE-THIRD CONSIN LOCK Application filed March 25,1925. Serial No. 18,263.

, Until recent years, cylinder type locks have been the symbol ofsecurity, but lately the manner ofpicking this type of lock has becomealmost general knowledge. Therefore, 5 this invention contemplates as aprimary object the provision of means for preventing the picking ofcylinder or similar type locks. A further object of this inventionresides in the provision of a lock cylinder having against picking whichwill not materially increase its cost of production and which in nowiseincreases its cost of installation or requires revision of the lockproper or other parts with which the cylinder is asso- 15 ciated.

With the above and other objects in view which will appear as thedescription proceeds, my invention resides in the novel construction,combination and arrangement of parts substantially as hereinafterdescribed and more particularly defined by the appended claims, it beingunderstood that such changes in the precise embodiment of thehereindisclosed invention may be made as come within the scope of theclaims.

In the accompanying drawing, I have illustrated one complete example ofthe physical embodiment of my invention constructed accordingto the bestmode I have so far devised for the practical application of theprinciples thereof, and in which:

Figure 1 is a sectional view through a lock cylinder, the key, tumblers,pins or drivers and pin or driver springs being in elevation and saidview being taken through Fig-' ure 4 on the plane of the line 11;

Figure 2 is a perspective view of the invided with hills and dales soarranged ner section of the improved plug;

Figure 3 is a perspective view of the outer section of my improved plug;

Figure 4 is a view taken transversely through the cylinder on the planeof the line 44 of Figure 1, and

Figure 5 is a view similar to Figure 4 taken through Figure 1 on theplane of the line 5 5;

Referring now more particularly to the accompanying drawing, the numeral5 designates the barrel or shell of a lock cylinder which is adapted tobe securedin a door frame,-'not shown, in a suitable manner, as byscrewmg 1ts threaded 1nner end 6 into the casing or box of the lock, notshown, with v which it is used, the barrel being held against retrogrademovement by set-screws, not shown, engaging slots 7 in the barrel sides.

OF MILWAUKEE, WISCONSIN, ASSIGNOR OF'ONE-THIRD T0 PHIL- TO IRA MILTONJONES, BOTH OF MILWAUKEE, WIS-.

As is customary, the lock proper, not shown,

is actuated from a cam or tail piece 8 secured to the inner end of aplug 9 by fastenings 10.

The plug 9 may be of the special construction later described and isprovided with a longitudinal key-way or slot 11 of irregular shape intransverse section to'conform with the irregularities of a key 12adapted to be inserted therein. Theportion of the plug directly abovethe key-way slot is provided with a plurality of spaced, longitudinallyaligned, radial apertures 13, the inner ends of which terminate in thekey-way and the outer ends of which are adapted to register with bores14 in the barrel or shell and radiating from the axis of the bore 15 inwhich the plug is rotatably mounted. Tumblers 16 of different lengthsare positioned in the openings 13 of the plug and cooperate with pins ordrivers 17 mounted in the barrel or shell bores 14. The lower ends ofthe tumblers are preferably slightly rounded and normally rest on thelowermost ridge or bead 11 of the key-way with the pins or drivers"extended into the openings 13 and yieldably held in engagement withtheir respective tumblers when the plug is in neutral position with theopenings and bores in" register by expansile springs 18. f The upper oractive edge of the key is proeasy task to open locks of this characterwithout a key, this being accomplished by placing ,a picking tool suchas a thin but stifi wirein the key-way and applying a rotational strainon the plu at the same time rapidly vibrating the pic 'ng tool. Thevibrating of the tumblers while a rotational stress is applied to theplug results in the catching of the pins or drivers in their bores afterthey have been freed of the plug so that when all of the pins or drivershave been so caught, the plug may be freely rotated to open the lock,not shown, connected therewith through the cam or tail piece 8.

In order to render the unauthorized actuation of the lock Cylinderdiflicult, if not impossible, the plug 9 may be formed in sections, asbest depicted in Figures 1, 2 and 3. The sections of the plug .aresecured against longitudinal separatlon, as later described, but arefree to rotate independently except when the key 12 is in place so thatin the event a picking method such as previously described is emp oyedonly the pins or drivers engaging the outer section of'the plug Will bedisengaged. Conse uently, on y the first or outer plug section is eed torotate, the inner plug section remaining locked against rotation by theiImer ins or drivers engaged in the openings 13 of the section, inasmuchas the rotational stress placed on the lug in the picking operation wasnot applie to the inner section.

The sections of the improved plug are connected by the interlockingconstruction illustrated in Figures 2 and 3, the outer end of the innersection being counter-bored, as at 19, and the wall of the counter-borebein back bored to form an annular groove or c annel 20. A pair ofspaced lugs or projections 21 are formed on the inner end of the outerplug section on opposite sides of the key-way and the ends of theprojections are extended laterally in opposite directions to providecars 22 adapted to track in the channel 20 to prevent longitudinalmovement between the sections, but permit their independent freerotational movement on a common axis. The sections of the plug areconnected by inserting one ear 22 in the channel 19 opposite the key-wayand placing the other ear 22 in the key-way in register with the channelwhen the sections are rotated with respect to each other to disalign theears and the key-way. The assembled plug is then positioned in the shellor barrel bore 15 and secured therein against lon itudinal movement bythe cam 8 at its rear an a flan e 23 on the outer end of the outersection an which fits in a counter-bore 24 in the barrel outer face, Theplug being confined in the bore 15, movement apart of the sectionsthereof in the event the ears 22 align with the key-way is prevented asthe plug sections must be moved transversely after the key-way and ears22 are in register to effect the separation of the sections.

In addition to the safe-guard against picking which is offered by thenovel two section plug previously described, I provide an additionalsafe-guard in the form of a tumbler 25 of reduced diameter and adaptedto be actuated by the extreme inner end 26 of the key. The tumbler 25Works in an opening 27 of the plug and its inner end is pointed for thereasons later described. The tumbler 25 cooperates with a pin or driver28 mounted in a bore 29 in the barrel or shell in line with the bores14, the pin or driver 28 being yieldably urged into the opening 27 whenin register with the bore 29 by an expansile spring 30.

The tumbler 25 being of reduced diameter and pointed at its lower endaffords added protection against picking, as the picking tool or othermember, which of necessity must be thin, cannot lift the tumbler to moveits pin 28 into the bore 29, but instead the pickin tool slides ofi toone side thereof. This difficulty is further increased by the locationof the tumbler 25 at the extreme inner end of the key-way.

In addition to the safe-guards against picking previously described,additional means are rovided, the form of two additional pins or rivers17 and 28' mounted in bores 14' and 29, respectively.

The bores 14 and 29 are arranged in a longitudinal line and intersectthe axis of the plug, and the bores 14' and 29, while intersecting theaxis of the plug, are disposed out of line with the bores 14 and 29,being positioned to the side thereof the plug is rotated toward itsunlocking movement. The bore 29 is in transverse alignment with the bore29 so that a rotation of the plug to openthe lock controlled from thecam 8 registers the opening 27 therewith after the .plug has partiallyrotated toward lock opening position, and with the tumbler 25 held inproper position by the key, the continued rotation of the plug isunrestricted.

The bore 14: is in transverse alignment with the innermost bore 14, andin longitudinal alignment with the bore 29. With the key in place theinnermost tumbler 16 and the tumbler 25 prevent the pins or drivers 17and 28' from entering the innermost opening 13 and the opening 27, andthus the plug is free to rotate. The pins or drivers 17 and 28 areyieldably urged outwardly of their bores by springs 18' and 30,respectively, the strength of which are greater than the other springs.

In the opening of the lock, the key is inserted in the mannerillustrated in Figure 1, as a result of which the tumblers all movetheir respective pins or drivers into the barrel or shell with the lineof break between the tumblers and pins or drivers in register with thewall of the bore 23, so that the plug may be freely rotated by the keyto rotate the cam or tail piece 8 and actuate the lock, not

shown, controlled therefrom. As the plug is rotated to open the lock,the innermost opening 13 and the opening 27 simultaneously register withthe bores 14 and 29, respectively, the ins or'drivers 17' and28' beingheld inoperalble by thetumblers which are held with their upper ends inline with the plug periphery, and the plug is free to'rotate.

However, assume that, in the event the plug is of the one-piece type anda picking tool of the vibrating or any other type has been actuated tosuccessfully align the'tops of the tumblers with the periphery of theplug to permit the rotation of the plug, as soon as the bores 14 and 29align with the innermost opening 13 and opening 27, the pins'or drivers17 and 28 engage therein, firmly locking the plug against furtherrotation.

With the plug thus locked by the pins or drivers 28 or 17 their releaseby a picking tool whether of the vibrating or any other type is renderedexceedingly diflicult if not impossible by reason of the fact that thetumblers 16 outwardly of the one in the opening in which the auxiliarypin or driver is engaged cannot be vibrated as their outer ends areengaged against the solid wall of the barrel or shell bore 15. In thisevent, the only manner in which the plug can be released and rotated is'by drilling through the pins or drivers, which results in thedestruction of the cylinder and requires its replacement with a new one.

As illustrated the inner small sharp tumbler preferably works on .theinner end of 'the key and the spring of its pin or driver 28 is of addedstrength. If desired, the auxil ,p s to pp iary nate by reason of thefact that it is practically impossible to vibrate the tumbler 25 withany type oi picking tool by reason of its pointed end, its smalldiameter and the comparatively heavy spring for its pin or driver.Further, the rovision of the sectional plug renders it di cult to pickas it is customary to insert a tool in the outer end of the the rotatingstress asthe tumblers are vibrated, which results in the releasing ofonly the pins or drivers cooperating with the first plug section. Thisis especially true as I have found it impractical to provide a meansinsertable in the key-way a distance sufiicient to connect the plugsections, as to do so reduces the vibrating space necessary to effectthe picking of the cylinder. Furthermore, any means extended through thekeyway to efiect the picking of the cylinder will have to be of suchreduced thickness as to render it impossibleto stand the strainnecessary to rotate the plug in the event the pins or drivers are movedto inactive position.

As stated, the auxiliary pins or drivers 14 and 27 may be eliminated,but they constitute an additional, positive safe-guard and ins ordrivers 14 and 27 may be elimior jointly and may may be used eithersingly longitudinal plane be arranged in a common,

or offset with respect to each other, as illusit will be readilyapparent to those skilled in the art to which an invention of thischaracter appertains, simple means for rendering a lock cylinder safeagainst unauthorized opening and one which may be added to locks now inuse or to looks at the time of their manufacture.

What I claim as my invention is: e 1. A look of class described,comprising a shell, a slotted plug rotatable therein and provided witha' lurality of tumbler sockets, tumblers mova le in the sockets, driversmounted in the shell and adapted to pass into the tumbler sockets whenthe plug is in a neutral position, said drivers being removed from theplug by the insertion of a that I provide a novel and key in the slotthereof, and one of said tumblers being of a smaller diameter than theothers and having its end portion pointed for engagement with theextreme end por.

tion of a key.

2. A device of the character described, comment of one section withrespect to the other,

drivers mounted in the shell, means normally tending to urge the driversinto openings in the plug sectlons when the sections are'rotated toregister their openings with the drivers, and tumblers in the plugopenings and operable upon the insertion of a proper key in the plugslot to connect the sections for joint rotation and free the drivers ofthe plug to permit its rotation as a unit.

3. A lock of the class described, comprising a shell, a sectional,slotted .plu rotatable therein, means for locking both sections againstrelative movement, and a second means for locking one of thesections'against unlawful rotation.

4. A look of the class described, comprising a shell, a sectional,slotted plug rotatable therein, key releasable means for locking bothsections against movement, and auxiliary in alignment with the lockingelements for I preventing the rotation of one section during theunauthorized movement of the other section.

6. A device of the character described, comprising a shell, a plugrotatable therein and consisting of two sections adapted to beoperatively connected by a key, tumblers mounted in sockets formed inthe plug sections, drivers carried by the shell and adapted to pass intothe tumbler sockets when the plug sections are in a neutral position,the insertion of a properly fitted key in the lug connecting thesections and moving the rivers free of the tumbler sockets to permit therotation of the plug sections as a unit, and means operable upon theunlawful rotation of one plug section a predetermined distance to lockthe same against continued rotation.

7. A device of the character described, comprising a shell, a plugrotatable therein and consisting of two sections adapted to beoperatively connected by a key, tumblers mounted in sockets formed inthe plug sections, and drivers carried by the shell and adapted to passintb the tumbler sockets when the plug sections are in a neutralposition, the insertion of a properly fitted key in the plug connectingthe sections and moving thev drivers free of the tumbler sockets topermit the rotation of the plug sections as a unit, the innermosttumbler of the inner plug section being of a smaller diameter than theothers and having its inner end portion pointed.

8. A device of the character described, comprising a shell, a plugrotatable therein and consisting of two sections adapted to be0peratively connected by a key, tumblers mounted in sockets formed inthe plug sections, drivers carried by the shell and adapted to passintothe tumbler sockets when the plug sections are in a neutralposition, the insertion of a properly fitted key in the plug connectingthe sections and moving the drivers free of the tumbler sockets topermit the rotation of the plug sections as a unit, the inner-mosttumbler of the inner plug sections being of a smaller diameter than theothers and having its inner end portion pointed, and means operable uponthe unlawful rotation of one plug section a predetermined distance tolock the same against continued rotation.

9. A device of the character described, comprising a shell, a plugrotatable therein and provided with a key slot, a plurality of lockingelements operatively accessible from points spaced longitudinally in theslot, means for breaking the continuity of said slot between certain ofsaid points on unauthorized rotation of said plug, and meansautomatically operable to prevent rotation of the plug to restorecontinuity of the slot.

10. A device of the character described, comprising a shell, a plugrotable therein and provided with a key slot, a plurality of lockingelements operatively accessible from said slot, means for distorting theslot on unauthorized rotation of the plug, and means operable byunauthorized rotation of the plug to lock the plug in slot distortedposition in the shell.

11. A device of the character described, comprising a'shell, a plugrotatable therein and provided with a key slot, a plurality of lockingelements operatively accessible from points spaced longitudinally in theslot, means for breaking the continuity of said slot between certain ofsaid oints upon unauthorized rotation of the plhg, and meansautomatically operable upon a predetermined degree of unauthorizedrotation of said plug to ock said plug against further movement in'innermost tumbler being of a smaller diamcter than the others and of asmaller diameter than the thickness of a'key, the inner end portion ofsaid smaller diameter tumbler being pointed and disposed for contactwith the extreme inner end of a key.

In testimony whereof I afiix my signature.

ARTHUR C. STEVENS.

